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Fletcher Munson Compensation - EQ curve suggestions?
by jimsreynolds on 2012-06-10 01:03:51

OK, I mainly use my HD500 for Effects support for my Marshall JVM but I have recently had an increased need to travel light and am therefore working to get my HD500 Modelled sounds up to snuff for live work. I don't have regular access to FRFR monitors, headphones or PA and am therefore taking a guerrilla approach to tonebuilding (create a bunch of similar test presets and quickly check which one sounds best when I use the house PA).  This has had varying degrees of success !

I am being hit by a common issue, whereby the sounds that work at lower volumes tend to get mushy at higher volumes due to the Fletcher-Munson Effect ( http://line6.com/support/docs/DOC-3787)and am looking for a go-to workaround for this.

I think that, in principle, I should be able to define a standard EQ setup that I can apply to my patches so that they get Fletcher-Munson-compensated when I crank up the volume.  OK, house PA responses will always differ a bit but If I can nail the main issues at source then hopefully the channel strip on a mixer can do the rest.  If I can get a good standard EQ then I can apply it using a footpedal assignment or maintain banks of High volume/Low volume patches

I am curious then?  Does anyone out there have a standard EQ setup (either on or off the POD) that they apply to correct for Fletcher Munson?



Re: Fletcher Munson Compensation - EQ curve suggestions?
by spaceatl on 2012-06-10 15:33:57

I don't really bother with it all that much these days...However, this is something I have used for many years as FOH engineer...Anyway, in terms of the HD Pod I have a couple of suggestions...My own opinion is that the players should not worry about this too much...A good engineer will guide you on this and compensate this accordingly...It is much easier to make this adjustment globally...But every situation is different and human hearing response as it relates to loudness is very key to understanding tone I think...a very healthy endeavor I think...and it is kinda fun to see how much these guys figured out back in 1933...

One would be to use the mid focus EQ...Basically, loudness compensation can be done with a single filter that is about 4-5 octaves wide centered around 1K...The interesting thing that we can do with the HD parm assignments is tie the cut/boost gain and output parameters of the EQ to an expression pedal...I have tinkered with this a little and you can approximate the output level compensation for cut/boost...basically, the idea is to try and keep the output voltage the same...It's not really possible to tie this to the master volume setting...Ideally, the cut/boost would depend on the master vol setting...but then there is the actual sound pressure also which is what this is really all about...Anyway, turning an expression pedal into a loudness morph is a very interesting idea...then again a global EQ in the FX loop can be a fairly simple approach to take...

It's been a few years since I read the paper, but the curves are in there and really as long as you get close it works...Basically it's the same thing a the loudness switch on a stereo...human hearing becomes fairly flat at higher sound pressures, more acute to a center frequncy of 1K at lower levels...That's basically it...FM effect always makes me chuckle a little bit...These were the first guys to map human hearing response scientifically for the analog telephone system...I see it as a response, not an effect...but that's just semantics...

Anyway, I think this is a great read for anyone that is truely interested in learning what the "effect" is and how to compensate for it...For me, being aware of it as long as I have I actually tweak for it all the time...most folks do...when you know that when you turn up the mids might start knocking your head off...The relationship of distortion to sound pressure is an interesting one also...much more complicated and that's kinda where separate tones come into play I think...



Re: Fletcher Munson Compensation - EQ curve suggestions?
by jimsreynolds on 2012-06-11 12:43:29

That's a great and comprehensive answer Space with some good suggestions.  Fascinating to see the original paper (even if my Math isn't good enough to hack it all)!



Re: Fletcher Munson Compensation - EQ curve suggestions?
by Akeron on 2012-06-12 08:34:20

Voxengo Span (a free Windows vst) has also k metering. These links could be interesting:

http://en.wikipedia.org/wiki/K-system

http://en.wikipedia.org/wiki/K-system">http://en.wikipedia.org/wiki/K-system

class="loading" href="http://forum.cakewalk.com/tm.aspx?m=1572420" title="http://forum.cakewalk.com/tm.aspx?m=1572420

http://forum.cakewalk.com/tm.aspx?m=1572420">http://forum.cakewalk.com/tm.aspx?m=1572420

class="comment">http://www.ultimatemetal.com/forum/andy-sneap/759056-loudness-war-presence-war.html

class="comment">



Re: Fletcher Munson Compensation - EQ curve suggestions?
by DeanDinosaur on 2012-06-12 10:53:05

how about putting a pod HD Parametric EQ at the end of the signal chain and boosting the highs and lows by about 4 to 6db while you make your patches. Then simply turn off the P EQ when you plug into the FOH. In theory this should correct for the exaggerated Lows and Highs that most players use too much off at low volume.



Re: Fletcher Munson Compensation - EQ curve suggestions?
by jimsreynolds on 2012-06-12 11:45:29

@Akeron - thanks for the links, I will have a look through.

@Dean - that was kind of where I was going, that or the Mid boost EQ (assuming the basic tones are initially setup for quiet).

Reading around the subject a bit more, It seems that SpaceATL's take - that Fletcher Munson is a useful reference but maybe not anything to get hung up on in the face of other factors - may be the sensible mindset.  I think that, rather than try setting up a standard EQ on my patches, I might grab a decent EQ Pedal to start with , hook it up downstream of the POD and try getting some kind of 'go to' curve using my ears rather than trying to do it too scientifically.  If I get something that is regular enough I can try and reproduce it using the POD EQ.   For now though I think I probably need the adjustability.



Re: Fletcher Munson Compensation - EQ curve suggestions?
by meambobbo on 2012-06-12 12:30:45

My advice is to dial in your patches as loud as possible in a good pair of headphones and monitors/PA.  It will sound fine at lower volumes as well, even if it doesn't sound like someone's a$$ is being kicked.  Trying to accurately recreate a FM curve is a challenge.  Even if you did so, you still wouldn't be able to dial in tones at low volume that are magically perfect at high volume.  But the reverse is not true - a tone dialed in at higher volume generally sounds good at lower volumes.



Re: Fletcher Munson Compensation - EQ curve suggestions?
by spaceatl on 2012-06-12 14:39:58

@jimsreynolds - thanks...I really enjoy chatting about this one...very interesting subject to me...So many ways to peel this onion.,..

+1 meambobbo...However, high gain patches are where things can get a little wierd I think..."relatively" speaking that is...

I don't think this is so much the Loudness:SPL phenom as it is the Saturation:SPL phenom...I don't have anything scientific to cite at the moment, but I know humans tend to equate loudness with a certain ratio of distortion. And I mean literal saturation. When I started mixing on extremely high power EAW-850 systems and EV Manifolds over some 20 years ago, I became very aware of this...With systems like that, you actually have to be very careful about the SPL...You really can hurt yourself (and others) because those systems can be so clean that you just don't realize that your ears are bleeding... :-) For someone like me that came up on underpowered JBL systems with a Soundcraft consoles it was a real eye opener...The more touring I did and the more systems I mixed on, this became even more obvious...I think this is a similar thing with guitar tone, but can be even more exagerrated...

Anyway, the one that always confounds me is leveling clean patches to very crunchy patches...What works on your own is very different that what works with the band...The crunchy patches will seem so much louder...So when the amp is cranked with the band, less distortion generally helps cut through...This becomes very important in two guitar situations...But then that relative level difference between the clean tone and the mega crunch tone in the alone situation vs with the band...

So you have the loudness response that changes with Sound Pressure and a distortion ratio that alters perception of loudness depending on the situation...It can get complicated...Add in how the room is playing into it and then things get really fun...



Re: Fletcher Munson Compensation - EQ curve suggestions?
by jimsreynolds on 2012-06-13 02:44:55

@Space ... yeah, I totally hear you on that clean/crunch balancing act.   Nails me quite badly on my JVM also.  Figured it had something to do with the decreased dynamics in a more distorted sound.  Once you hit full overdrive it gets a bit easier but that transitional thing is a real pain to get right ... often I end up tweaking mid performance and that makes me few friends.

@Meambobbo.   Thanks.   I think there is a growing weight of evidence that my next big purchase should be a decent set of cans!  Out of interest:  when you do your tone building are you shooting mainly for a good tone for recordings or for live ... or both?



Re: Fletcher Munson Compensation - EQ curve suggestions?
by DeanDinosaur on 2012-06-13 09:24:46

jimsreynolds wrote:

   I think there is a growing weight of evidence that my next big purchase should be a decent set of cans! 

The worst idea possible to make patches using headphones....they don't translate correctly, you might as well plug into your stereo system (even a small boombox (from a mixer) and that will translate much better for Patches to use into PA or any FRFR, than the most expensive headphone that money can buy.



Re: Fletcher Munson Compensation - EQ curve suggestions?
by spaceatl on 2012-06-13 09:31:37

One of the best features I think Line 6 ever had to combat this was the global EQ on the AX2...I never had any trouble going room to room with that amp....just tinker with the global EQ and I was set....

In terms of the crunch thing vs volume, I did have a little solution for it that worked really nicely on my old Flextone IIIXL rig....Basically, I have an ADA MP-1 (GTR->MP1->Flexy GTR Input)...midi from the Flexy control patch changes on the ADA...however the usage of the ADA was not for the tube preamp as much as it was for the programable EQ tonestack...It supplemented the Flextone tone stack quite nicely where I could keep it closer to flat which always made XT hardware sound better to me...anyway, a patch could also push the amp model a bit with clean voltage....Anyway, what I found was that between the master volume of the ADA and the master volume of the Flexy, I could make a small adjustment to how hard the amp model was getting hit in global way...This actually worked pretty darn well...If I turned the Flexy master down, I could crank up the master on the ADA a little bit and get just a bit more sustain....If I was cranking the Flexy master, I could back off my crunchy tone using the ADA master to clean it up a skosh...Probably one of the best cover rigs I have ever had...Just a little too big with the 10 space rack....I had a parallel loop as I had a sub mixer in the rack to pickup some other FX I needed...fun while it lasted...but it made my back hurt too much...



Re: Fletcher Munson Compensation - EQ curve suggestions?
by meambobbo on 2012-06-13 09:35:16

"when you do your tone building are you shooting mainly for a good tone for recordings or for live"

I don't think there should necessarily be a difference.  Most of my tones are matching an artist.  So there I'm going for trying to get the recorded sound, even if I have some ideas on how I could improve the tone.  But in general, I think a tone should sound great both on a recording and live, without any different tweaking.  If anything there might be some additional EQ'ing done on a recording to improve how a mix sounds, so each instrument stands out a bit more.  I also think this is good practice for a live situation, but you have much more control in the studio.  But that's using studio software.  Using the Pod, I shoot for the same tone live vs. studio.



Re: Fletcher Munson Compensation - EQ curve suggestions?
by meambobbo on 2012-06-13 09:39:20

Most of my tones I make using Sennheiser HD 280 Pro's - not exactly expensive or studio-quality headphones.  But they have enough range and a flat enough response to get me sounding where I know the sound is good.

Dialing in patches on monitors or a PA is much worse in my opinion IF you aren't using a treated room.  My room has all kinds of bass nodes, so I have to walk all around the room as I'm playing to get even a mildly decent impression of what the actual tone is.

Most of my success comes from making sure my tone is good both in the cans and all around the room using the monitors.



Re: Fletcher Munson Compensation - EQ curve suggestions?
by meambobbo on 2012-07-13 16:58:16

I don't think the gain on the mid-focus eq affects the level of filtering only the output level of the effect. Even at 0% the effect still affects the tone. So I would think you'd need to use the parametric to obtain the expression pedal effect you mentioned.



Re: Fletcher Munson Compensation - EQ curve suggestions?
by spaceatl on 2012-07-13 17:16:42

Yes sir, I agree with you on that...A real parametric would be better...Personally, I wish they would model a pultec as UAD has me spoiled on that one...

My mistake on the mid-focus, I was thinking outloud on that one...I have done some expression eq parms for morphing a lead boost...The mid focus is the one I use for that...more complicated with the low end and high end rolling off with the gain going up...very cool with tones that are low enough gain where it works in front of the amp model to push it harder in tandem...



Re: Fletcher Munson Compensation - EQ curve suggestions?
by jimsreynolds on 2012-07-14 01:34:57

As a subscript:have invested in an MXR Ten band EQ now, as a global EQ for the POD and general fun tone-shapery with my real amp.  Went fo the Kerry King version which has a useful second 1/4" output (output to monitor and PA perhaps) and a tattoo graphic that makes me feel more manly.

Will experiment with this and report back (eventually, limited gigging at the moment).




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